diff --git a/clickhouse-activerecord.gemspec b/clickhouse-activerecord.gemspec
index 14befddf..caa4efb8 100644
--- a/clickhouse-activerecord.gemspec
+++ b/clickhouse-activerecord.gemspec
@@ -24,7 +24,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
 
   spec.add_dependency "bundler", ">= 1.13.4"
-  spec.add_dependency 'activerecord', '>= 5.0'
+  spec.add_dependency 'activerecord', '>= 5.2'
 
   spec.add_development_dependency 'bundler', '~> 1.15'
   spec.add_development_dependency 'rake', '~> 10.0'
diff --git a/lib/active_record/connection_adapters/clickhouse/oid/big_integer.rb b/lib/active_record/connection_adapters/clickhouse/oid/big_integer.rb
index 5f73d2aa..bfddeaae 100644
--- a/lib/active_record/connection_adapters/clickhouse/oid/big_integer.rb
+++ b/lib/active_record/connection_adapters/clickhouse/oid/big_integer.rb
@@ -5,8 +5,9 @@ module ConnectionAdapters
     module Clickhouse
       module OID # :nodoc:
         class BigInteger < Type::BigInteger # :nodoc:
-
-          DEFAULT_LIMIT = 8
+          def type
+            :big_integer
+          end
 
           def limit
             DEFAULT_LIMIT
diff --git a/lib/active_record/connection_adapters/clickhouse/schema_creation.rb b/lib/active_record/connection_adapters/clickhouse/schema_creation.rb
index 2851c7b8..9eeea336 100644
--- a/lib/active_record/connection_adapters/clickhouse/schema_creation.rb
+++ b/lib/active_record/connection_adapters/clickhouse/schema_creation.rb
@@ -4,23 +4,24 @@ module ActiveRecord
   module ConnectionAdapters
     module Clickhouse
       class SchemaCreation < AbstractAdapter::SchemaCreation# :nodoc:
+
         def visit_AddColumnDefinition(o)
           +"ADD COLUMN #{accept(o.column)}"
         end
 
         def add_column_options!(sql, options)
-          if options[:null] == true
-            sql.gsub(/\s+(.*)/, ' Nullable(\1)')
-          else
-            sql
+          if options[:null] || options[:null].nil?
+            sql.gsub!(/\s+(.*)/, ' Nullable(\1)')
           end
+          sql.gsub!(/(\sString)\(\d+\)/, '\1')
+          sql
         end
 
         def add_table_options!(create_sql, options)
-          if engine_sql = options[:options]
-            create_sql << " ENGINE=#{engine_sql}"
+          if options[:options].present?
+            create_sql << " ENGINE = #{options[:options]}"
           else
-            create_sql << " ENGINE=Log()"
+            create_sql << " ENGINE = Log()"
           end
 
           create_sql
diff --git a/lib/active_record/connection_adapters/clickhouse/schema_definitions.rb b/lib/active_record/connection_adapters/clickhouse/schema_definitions.rb
index 6ccb4160..e101dc7a 100644
--- a/lib/active_record/connection_adapters/clickhouse/schema_definitions.rb
+++ b/lib/active_record/connection_adapters/clickhouse/schema_definitions.rb
@@ -4,6 +4,15 @@ module ActiveRecord
   module ConnectionAdapters
     module Clickhouse
       class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
+
+        def integer(*args, **options)
+          if options[:limit] == 8
+            args.each { |name| column(name, :big_integer, options.except(:limit)) }
+          else
+            super
+          end
+        end
+
       end
     end
   end
diff --git a/lib/active_record/connection_adapters/clickhouse/schema_statements.rb b/lib/active_record/connection_adapters/clickhouse/schema_statements.rb
index de3e7656..2b68dd45 100644
--- a/lib/active_record/connection_adapters/clickhouse/schema_statements.rb
+++ b/lib/active_record/connection_adapters/clickhouse/schema_statements.rb
@@ -33,6 +33,42 @@ def tables(name = nil)
           result['data'].flatten
         end
 
+        def table_options(table)
+          sql = do_system_execute("SHOW CREATE TABLE #{table}")['data'].try(:first).try(:first)
+          { options: sql.gsub(/^(?:.*?)ENGINE = (.*?)$/, '\\1') }
+        end
+
+        # @todo copied from  ActiveRecord::ConnectionAdapters::SchemaStatements v5.2.2
+        # Why version column type of String, but insert to Integer?
+        def assume_migrated_upto_version(version, migrations_paths)
+          migrations_paths = Array(migrations_paths)
+          version = version.to_i
+          sm_table = quote_table_name(ActiveRecord::SchemaMigration.table_name)
+
+          migrated = ActiveRecord::SchemaMigration.all_versions.map(&:to_i)
+          versions = migration_context.migration_files.map do |file|
+            migration_context.parse_migration_filename(file).first.to_i
+          end
+
+          unless migrated.include?(version)
+            do_execute( "INSERT INTO #{sm_table} (version) VALUES (#{quote(version.to_s)})", 'SchemaMigration', format: nil)
+          end
+
+          inserting = (versions - migrated).select { |v| v < version }
+          if inserting.any?
+            if (duplicate = inserting.detect { |v| inserting.count(v) > 1 })
+              raise "Duplicate migration #{duplicate}. Please renumber your migrations to resolve the conflict."
+            end
+            if supports_multi_insert?
+              do_system_execute insert_versions_sql(inserting)
+            else
+              inserting.each do |v|
+                do_system_execute insert_versions_sql(v)
+              end
+            end
+          end
+        end
+
         # Not indexes on clickhouse
         def indexes(table_name, name = nil)
           []
diff --git a/lib/active_record/connection_adapters/clickhouse_adapter.rb b/lib/active_record/connection_adapters/clickhouse_adapter.rb
index c5b923ee..f9df50bc 100644
--- a/lib/active_record/connection_adapters/clickhouse_adapter.rb
+++ b/lib/active_record/connection_adapters/clickhouse_adapter.rb
@@ -8,6 +8,7 @@
 require 'active_record/connection_adapters/clickhouse/schema_definitions'
 require 'active_record/connection_adapters/clickhouse/schema_creation'
 require 'active_record/connection_adapters/clickhouse/schema_statements'
+require 'net/http'
 
 module ActiveRecord
   class Base
@@ -15,7 +16,7 @@ class << self
       # Establishes a connection to the database that's used by all Active Record objects
       def clickhouse_connection(config)
         config = config.symbolize_keys
-        host = config[:host]
+        host = config[:host] || 'localhost'
         port = config[:port] || 8123
 
         if config.key?(:database)
@@ -124,11 +125,13 @@ def valid_type?(type)
 
       def extract_limit(sql_type) # :nodoc:
         case sql_type
-          when 'Nullable(String)'
-            255
-          when /Nullable\(U?Int(8|16)\)/
-            4
-          when /Nullable\(U?Int(32|64)\)/
+          when /(Nullable)?\(?String\)?/
+            super('String')
+          when /(Nullable)?\(?U?Int8\)?/
+            super('int2')
+          when /(Nullable)?\(?U?Int(16|32)\)?/
+            super('int4')
+          when /(Nullable)?\(?U?Int(64)\)?/
             8
           else
             super
@@ -137,18 +140,17 @@ def extract_limit(sql_type) # :nodoc:
 
       def initialize_type_map(m) # :nodoc:
         super
-        register_class_with_limit m, 'String', Type::String
-        register_class_with_limit m, 'Nullable(String)', Type::String
-        register_class_with_limit m, 'Uint8', Type::UnsignedInteger
+        register_class_with_limit m, %r(String), Type::String
         register_class_with_limit m, 'Date',  Clickhouse::OID::Date
         register_class_with_limit m, 'DateTime',  Clickhouse::OID::DateTime
-        m.alias_type 'UInt16', 'uint4'
-        m.alias_type 'UInt32', 'uint8'
-        m.register_type 'UInt64', Clickhouse::OID::BigInteger.new
-        m.alias_type 'Int8', 'int4'
-        m.alias_type 'Int16', 'int4'
-        m.alias_type 'Int32', 'int8'
-        m.alias_type 'Int64', 'UInt64'
+        register_class_with_limit m, %r(Uint8), Type::UnsignedInteger
+        m.alias_type 'UInt16', 'UInt8'
+        m.alias_type 'UInt32', 'UInt8'
+        register_class_with_limit m, %r(UInt64), Type::UnsignedInteger
+        register_class_with_limit m, %r(Int8), Type::Integer
+        m.alias_type 'Int16', 'Int8'
+        m.alias_type 'Int32', 'Int8'
+        register_class_with_limit m, %r(Int64), Type::Integer
       end
 
       # Executes insert +sql+ statement in the context of this connection using
@@ -163,6 +165,10 @@ def primary_key(table_name) #:nodoc:
         false
       end
 
+      def create_schema_dumper(options) # :nodoc:
+        ClickhouseActiverecord::SchemaDumper.create(self, options)
+      end
+
       protected
 
       def last_inserted_id(result)
diff --git a/lib/clickhouse-activerecord/schema_dumper.rb b/lib/clickhouse-activerecord/schema_dumper.rb
index e3af8055..2639b919 100644
--- a/lib/clickhouse-activerecord/schema_dumper.rb
+++ b/lib/clickhouse-activerecord/schema_dumper.rb
@@ -1,5 +1,5 @@
 module ClickhouseActiverecord
-  class SchemaDumper < ActiveRecord::SchemaDumper
+  class SchemaDumper < ::ActiveRecord::ConnectionAdapters::SchemaDumper
 
     def table(table, stream)
       stream.puts "  # TABLE: #{table}"
diff --git a/spec/cases/migration_spec.rb b/spec/cases/migration_spec.rb
index d86219a2..c21fd8e1 100644
--- a/spec/cases/migration_spec.rb
+++ b/spec/cases/migration_spec.rb
@@ -61,11 +61,13 @@
 
               current_schema = schema(model)
 
-              expect(current_schema.keys.count).to eq(2)
+              expect(current_schema.keys.count).to eq(3)
               expect(current_schema).to have_key('id')
               expect(current_schema).to have_key('money')
+              expect(current_schema).to have_key('balance')
               expect(current_schema['id'].sql_type).to eq('UInt32')
-              expect(current_schema['money'].sql_type).to eq('Decimal(16, 4)')
+              expect(current_schema['money'].sql_type).to eq('Nullable(Decimal(16, 4))')
+              expect(current_schema['balance'].sql_type).to eq('Decimal(32, 2)')
             end
           end
         end
@@ -98,7 +100,7 @@
         expect(current_schema).to have_key('new_column')
         expect(current_schema['id'].sql_type).to eq('UInt32')
         expect(current_schema['date'].sql_type).to eq('Date')
-        expect(current_schema['new_column'].sql_type).to eq('UInt64')
+        expect(current_schema['new_column'].sql_type).to eq('Nullable(UInt64)')
       end
     end
 
diff --git a/spec/fixtures/migrations/add_sample_data/1_create_events_table.rb b/spec/fixtures/migrations/add_sample_data/1_create_events_table.rb
index a39417f4..5da04c4c 100644
--- a/spec/fixtures/migrations/add_sample_data/1_create_events_table.rb
+++ b/spec/fixtures/migrations/add_sample_data/1_create_events_table.rb
@@ -3,8 +3,8 @@
 class CreateEventsTable < ActiveRecord::Migration[5.0]
   def up
     create_table :events, options: 'MergeTree(date, (date, event_name), 8192)' do |t|
-      t.string :event_name
-      t.date :date
+      t.string :event_name, null: false
+      t.date :date, null: false
     end
   end
 end
diff --git a/spec/fixtures/migrations/dsl_add_column/1_create_some_table.rb b/spec/fixtures/migrations/dsl_add_column/1_create_some_table.rb
index de37d5e3..2435e2c6 100644
--- a/spec/fixtures/migrations/dsl_add_column/1_create_some_table.rb
+++ b/spec/fixtures/migrations/dsl_add_column/1_create_some_table.rb
@@ -3,7 +3,7 @@
 class CreateSomeTable < ActiveRecord::Migration[5.0]
   def up
     create_table :some, options: 'MergeTree(date, (date), 8192)' do |t|
-      t.date :date
+      t.date :date, null: false
     end
   end
 end
diff --git a/spec/fixtures/migrations/dsl_drop_column/1_create_some_table.rb b/spec/fixtures/migrations/dsl_drop_column/1_create_some_table.rb
index de37d5e3..2435e2c6 100644
--- a/spec/fixtures/migrations/dsl_drop_column/1_create_some_table.rb
+++ b/spec/fixtures/migrations/dsl_drop_column/1_create_some_table.rb
@@ -3,7 +3,7 @@
 class CreateSomeTable < ActiveRecord::Migration[5.0]
   def up
     create_table :some, options: 'MergeTree(date, (date), 8192)' do |t|
-      t.date :date
+      t.date :date, null: false
     end
   end
 end
diff --git a/spec/fixtures/migrations/dsl_drop_table/1_create_some_table.rb b/spec/fixtures/migrations/dsl_drop_table/1_create_some_table.rb
index de37d5e3..2435e2c6 100644
--- a/spec/fixtures/migrations/dsl_drop_table/1_create_some_table.rb
+++ b/spec/fixtures/migrations/dsl_drop_table/1_create_some_table.rb
@@ -3,7 +3,7 @@
 class CreateSomeTable < ActiveRecord::Migration[5.0]
   def up
     create_table :some, options: 'MergeTree(date, (date), 8192)' do |t|
-      t.date :date
+      t.date :date, null: false
     end
   end
 end
diff --git a/spec/fixtures/migrations/dsl_table_with_decimal_creation/1_create_some_table.rb b/spec/fixtures/migrations/dsl_table_with_decimal_creation/1_create_some_table.rb
index 068fa84b..3aedb806 100644
--- a/spec/fixtures/migrations/dsl_table_with_decimal_creation/1_create_some_table.rb
+++ b/spec/fixtures/migrations/dsl_table_with_decimal_creation/1_create_some_table.rb
@@ -4,6 +4,7 @@ class CreateSomeTable < ActiveRecord::Migration[5.0]
   def up
     create_table :some do |t|
       t.decimal :money, precision: 16, scale: 4
+      t.decimal :balance, precision: 32, scale: 2, null: false, default: 0
     end
   end
 end
diff --git a/spec/fixtures/migrations/dsl_table_with_engine_creation/1_create_some_table.rb b/spec/fixtures/migrations/dsl_table_with_engine_creation/1_create_some_table.rb
index de37d5e3..2435e2c6 100644
--- a/spec/fixtures/migrations/dsl_table_with_engine_creation/1_create_some_table.rb
+++ b/spec/fixtures/migrations/dsl_table_with_engine_creation/1_create_some_table.rb
@@ -3,7 +3,7 @@
 class CreateSomeTable < ActiveRecord::Migration[5.0]
   def up
     create_table :some, options: 'MergeTree(date, (date), 8192)' do |t|
-      t.date :date
+      t.date :date, null: false
     end
   end
 end